hulk inclusion category: bugfix bugzilla: 189183, https://gitee.com/openeuler/kernel/issues/I7Z1ZU CVE: NA

--------------------------------

This reverts commit 616e708277a2 ("memcg: fix a UAF problem in drain_all_stock()"), which was produced based on HULK-7.5 and later was found to be not suitable for HULK-8.1/4.19.

Fixes: 616e708277a2 ("memcg: fix a UAF problem in drain_all_stock()") Signed-off-by: GONG, Ruiqi gongruiqi1@huawei.com --- mm/memcontrol.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 29d430885b1a..7dc68b1792ef 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2232,7 +2232,8 @@ static void drain_all_stock(struct mem_cgroup *root_memcg)

rcu_read_lock(); memcg = stock->cached; - if (memcg && mem_cgroup_is_descendant(memcg, root_memcg)) + if (memcg && stock->nr_pages && + mem_cgroup_is_descendant(memcg, root_memcg)) flush = true; rcu_read_unlock();